offload: Allow testing machines that match a regexp.

* guix/scripts/offload.scm (check-machine-availability): Add 'pred'
parameter and honor it.
(guix-offload): for the "test" sub-command, accept an extra 'regexp'
parameter.  Pass a second argument to 'check-machine-availability'.

1 files changed, 6 insertions, 0 deletions

diff --git a/doc/guix.texi b/doc/guix.texi
index 71de73b953..0cb1bc7665 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -1005,6 +1005,12 @@ command line:
 # guix offload test machines-qualif.scm
 @end example
 
+Last, you can test the subset of the machines whose name matches a
+regular expression like this:
+
+@example
+# guix offload test machines.scm '\.gnu\.org$'
+@end example
 
 @node Invoking guix-daemon
 @section Invoking @command{guix-daemon}